An ICN is a conceptualization of the networking protocol stack, in particular layers 3 and above of a network protocol stack. A CCN is a particular architecture and implementation of an ICN. ICNs and CCNs are based on the premise of naming resources in these networks. In particular the naming relates to the use of a globally shared namespace for objects that allows entities in these networks to retrieve any content of interest.
Thus, with a CCN a name is utilized to identify a content object instead of an Internet Protocol (IP) address of the content or a host of the content. In an IP network, routing is based on host names (e.g., source and destination addresses). In a CCN by contrast, routing is based on a uniform resource identifier (URI) or similar identifier for a content object. CCN routing is performed hop-by-hop, using a longest prefix matching on the CCN name. All communications seeking to access data are framed as a request and response transaction. A CCN client sends a message referred to as a CCN interest to the nodes in the CCN. The nodes of the CCN respond with a content object identified by a CCN name in the CCN interest. These CCN content objects are returned via a CCN response. Content object packets follow the reverse path of the corresponding Interest. The reverse path is computed based on state left by Interest packets at each node, in a database called the PIT (Pending Interest Table).
All content object packets are cryptographically signed by their initial provider. A CCN client can thus verify the integrity and authenticity of the content even if the packet comes from untrusted links or untrusted hosts. As a direct effect, CCN nodes in the CCN network are allowed to cache packets locally in a table called the content store. When a CCN network node receives a CCN interest packet, it can check whether its local content store has the requested content object and can send it back if found. The look up in the content store is by the CCN name. If the CCN name is not found in the local content store, then the CCN interest is forwarded according to entries for the CCN name in a forwarding information base (FIB) of the CCN network node.
Mobility in a communication network requires handover support which refers to the process of transferring an ongoing call or data session from one data path connected to the core network to another data path. When a mobile device is moving away (e.g., as a result of their geographical movement) from the area covered by the access point which connects the mobile device to the communication network, and enters an area covered by another access point providing access to the same communication network or to another communication network, a handover or a roaming procedure is performed. In other cases, the handover may be performed if the current access point covering the mobile device reaches a maximum capacity, a new or existing call or data transfer can be transferred to another access point for connecting the mobile device to the network.